Selectively operable intermittent motion apparatus



Mayil3, 1969 J. J. SCHWEIHS Sheet INVENTOR. JESS J. SCHWEIHS FIG,3

May 13, 1969 J. J. SCHWEIHS SELECTIVELY OPERABLE INTERMITTENT MOTION APPARATUS Sheet of2 Filed June 21, 1967 MAGNET 70 FIG.6

1 REVOLUTION-I INCREMENTING WHEEL ESCAPE WHEEL I TOOTH ADVANCE j 0F ESCAPE WHEEL United States Patent 3,443,442 SELECTIV ELY OPERABLE INTERMITTENT MOTION APPARATUS Jess J. Schweihs, Rochester, Minn., assignor to International Business Machines Corporation, Armonk, N.Y.,

a corporation of New York Filed June 21, 1967, Ser. No. 647,721 Int. Cl. F16h 27/10 US. Cl. 74-15 11 Claims ABSTRACT OF THE DISCLOSURE Spring teeth on the escape wheel include a dwell section and a section which can deflect laterally to permit escape of a tooth on the incrementing wheel. The rate of incrementing is determined by the speed of the escape wheel and the amount of torque furnished 'by the coil spring.

A selectively operable magnet controls the incrementing operation. To stop incrementing, the magnet is operated during a dwell time to release its armature which engages a tooth on the incrementing wheel. The input shaft continues to rotate; however, the spiral spring is wound until slippage occurs between the friction shoe and the input'drum. Likewise, the escape wheel continues to rotate freely between a pair of teeth on the incrementing wheel. To resume incrementing, the armature is disengaged during a dwell time from the incrementing wheel. An emitter fixed to the escape wheel shaft provides an electrical control pulse for each dwell time.

BACKGROUND OF THE INVENTION Field of the invention This invention generally relates to improved intermittent motion apparatus and more particularly to such apparatus which is selectively operable, and still more particularly to selectively operable intermittent motion apparatus where the input shaft rotates continuously at a constant speed, even while incrementing has been stopped.

Description of the prior art Prior art devices such as well-known cam and pin gear drives provide for intermittent motion but are not selectively operable. Further, if the input rotates continuously, the output shaft cannot be stopped. The present invention is selectively operable and the output shaft can be held against movement while the input rotates continuously. This is possible because the input drum slips relative to the friction shoe when the incrementing wheel is held stationary.

SUMMARY OF THE INVENTION The principal object of the invention is to provide improved selectively operable intermittent motion apparatus which:

(a) does not require close tolerances;

(b) is relatively inexpensive;

(c) does not require detenting;

(d) is not affected by wear with regard to incrementing accuracy; and

(e) is relatively compact.

Patented May 13, 1969 FIG. 1 is an exploded isometric view of the device without the support structure;

FIG. 2 is a front elevational view of the device;

:FIG. 3 is a sectional view taken along the lines 33 in FIG. 2;

FIG. 4 is an enlarged exploded isometric view of the incrementing and escape wheels;

FIG. 5 is a schematic developed view illustrating how the incrementing wheel exits from the escape wheel;

FIG. 6 is a diagram illustrating the energization and de-energization of the magnet, the emitter pulses, the motion of the incrementing wheel and the motion of the escape wheel; and,

FIG. 7 is a view showing an alternate embodiment of the escape wheel.

DESCRIPTION With reference to the drawings, and particularly to FIGS. 1, 2 and 3, the invention is shown by way of example with input gear 10 fixed to shaft 11. Gear .10 is driven from a suitable source, not shown. Gear 12 is also fixed to shaft 11 and it meshes with gear 13 fixed to shaft 14. Worm 15 fixed to shaft 14 to rotate therewith meshes with worm gear 16, which is journaled on output shaft 17 by means of needle bearing 18. Shafts 11, 14 and 17 are suitably supported for rotation by housing 19.

Drum 20 is fixed to sleeve 21 which is integral with gear 16. An annular outwardly opening recess 22 in drum 20 receives an assembly consisting of spiral spring 25, expander 26 and friction shoe 27. Shoe 27 is fixed, as by bonding, to the outer convolution of spring 25. In fact, only a short arcuate section of the inner peripheral surface of shoe 27 is bonded to the outer convolution of spring 25. The outer peripheral surface of shoe 27 is adapted to engage the inner peripheral surface of drum wall 23.

The inner convolution of spring 25 is provided with the circular opening 30, FIG. 4, for receiving the end of pin 31. Additionally, pin 31 extends through hub 32 of incrementing wheel 33 and through shaft 17 to fix wheel 33 to shaft 17. Expander 26 is compressed upon insertion between a convolution of spring 25 and shoe 27 so as to normally hold shoe 27 in pressure contact with the inner peripheral surface of drum wall 23. Of course, as drum 20 rotates, spring 25 is wound via shoe 27 with the coils drawn inwardly. Expander 26 is further compressed and when maximum torque is reached, slippage occurs between friction shoe 27 and the inner peripheral surface of drum wall 23.

Movement of the incrementing wheel 33 is under control of an escape wheel assembly 40. Assembly 40 consists of a spring toothed escape wheel 41 sandwiched between backing plate 42 and receptacle plate 43. Plate 43 is provided with hub 44 for rigid attachment to shaft 11. Machine screws 45 pass through holes 46 and 47 in plate 42 and wheel 41 respectively and thread into tapped holes 48 in receptacle plate 43 to hold the elements in an assembled relationship.

In this example of the invention, escape wheel 41 has four teeth 50 as best seen in FIG. 4. Each tooth 50' has a rigid portion A and a laterally defiectable portion B. Receptacle plate 43 is provided with an angular recess 53 for receiving the defiectable portion B. The amount of lateral deflection of the portion B is determined by the circular pitch of the teeth on the incrementing wheel 33. Portion A is held rigid between plates 42 and 43. Thus the A portion of tooth 50 determines the length of dwell of the incrementing wheel 33. The B portion controls the escapement of the incrementing wheel 33. The rate of incrementing is determined by the speed of the escape wheel and the amount of torque provided by spring 25.

Escape wheel assembly 40 is a preferred embodiment because it provides continuous control over the incrementing wheel 33. As one tooth of the incrementing wheel 33 escapes, the following incrementing wheel tooth has engaged the A portion of the next escape wheel tooth. This is best illustrated in FIGS. 4 and 5 and particularly in FIG. 5, where tooth 33a has just escaped from wheel 41 and the A portion of the following tooth of the escape wheel 41 is in engagement with tooth 3312 so as to cause incrementing wheel 33 to dwell.

An alternate form of an escape wheel is shown in FIG. 7. The teeth 61 of escape wheel 60 are rigid and are separated by slots 62. The teeth 61 have a straight portion 63 which functions as a dwell and an angular portion 64 for controlling the advancement of the incrementing wheel 33. As one tooth on the incrementing wheel 33 exits through slot 62, the next tooth on the incrementing wheel engages the dwell portion of the next tooth on the escape wheel.

Incrementing wheel 33 can be selectively stopped by means of magnet 70, FIGS. 1, 2 and 3. Magnet 70 is provided with a coil 71 which embraces pole piece 72. Armature 73 is pivoted at 74 and is normally urged away from pole piece 72 by compression spring 75. Thus when magnet 70 is dc-energized, spring 75 urges armature 73 into engagement with a tooth on incrementing wheel 33. When this occurs, the teeth of the escape wheel 41 rotate freely between adjacent teeth on the incrementing wheel 33. The magnet 70 is energized or de-energized always during the time when a dwell portion of the escape tooth is in engagement with a tooth on the incrementing wheel 33.

A magnetic emitter assembly 80 consisting of emitter wheel 81 and sensing head 82 provides an electrical impulse at the beginning of each dwell time. Emitter wheel 81 is fixed to shaft 11 and is provided with four arcuately spaced ferromagnetic projections 83. As wheel 81 is rotated by shaft 11, projections 83 successively pass sensing head 82. Sensing head 82 is of the well known reluctance type magnetic pickup head and it generates an electrical impulse as projections 83 pass relative thereto. These repetitive electrical impulses are shown in FIG. 6. It is also seen in FIG. 6 that magnet 70 is turned on and olf only at a dwell time. The escape wheel 41 rotates continuously; however, the incrementing wheel 33 is free to rotate only when magnet 70 is energized. Magnet 70 can be energized from any suitable source. During one revolution of the escape wheel, only three teeth of the incrementing wheel have escaped. This is because magnet 70 was de-energized during a portion of the revolution of escape wheel 41.

In summary, input shaft 11 rotates continuously so as to continuously rotate escape wheel assembly 40 and drum 20 via gears 12 and 13, shaft 14, worm and gear 16. During the time that the dwell portion A of an escape wheel tooth 50 is in engagement with a tooth of incrementing wheel 33, drum winds spring through friction shoe 27. Thereafter, when escape wheel 41 has rotated to a position to permit a tooth on incrementing wheel 33 to escape, spring 25 unwinds to advance the incrementing wheel 33. Of course, incrementing wheel 33 can only advance if magnet 70 is energized so as to disengage armature 73 from incrementing wheel 33.

What is claimed is:

1. Intermittent motion apparatus comprising:

an incrementing wheel mounted for rotation and having arcuately spaced teeth around the periphery thereof,

means for constantly urging said incrementing wheel to rotate,

a constantly driven escape wheel having a predetermined number of teeth and mounted to rotate with the teeth thereof in engagement with the teeth of said incrementing wheel to control the movement of said incrementing wheel, said teeth on said escape wheel having a dwell portion and a portion enabling escapement of an incrementing wheel tooth, and means selectively operable to engage said incrementing wheel to hold the same stationary as said escape wheel continues to rotate. 2. Intermittent motion apparatus comprising: an incrementing wheel mounted for rotation and having arcuately spaced teeth around the periphery thereof, means for constantly urging said incrementing wheel to rotate, and a constantly driven escape wheel having a predetermined number of teeth and mounted to rotate with the teeth thereof in engagement with the teeth of said incrementing wheel to control the movement of said incrementing wheel, said teeth on said escape wheel having a dwell portion and a portion enabling escapement of an incrementing wheel tooth, said means constantly urging said incrementing wheel to rotate comprising: a constantly driven drum having an interior recess, a friction shoe disposed within said interior recess, and a spiral spring having a portion of an inner convolution connected to said incrementing Wheel and a portion of an outer convolution connected to said friction shoe. 3. The intermittent motion apparatus of claim 2 further comprising:

an expander element positioned between a convolution of said spring and said shoe so as to normally urge said shoe in pressure contact with said drum. 4. Intermittent motion apparatus comprising: an incrementing wheel mounted for rotation and having arcuately spaced teeth around the periphery thereof, means for constantly urging said incrementing Wheel to rotate, and a constantly driven escape wheel having a predetermined number of teeth and mounted to rotate with the teeth thereof in engagement with the teeth of said incrementing wheel to control the movement of said incrementing wheel, said teeth on said escape wheel having a dwell portion and a portion enabling escapement of an incrementing wheel tooth, the teeth of said escape wheel being arcuately spaced from each other by an amount equal to the width of the teeth on said incrementing wheel. 5. Intermittent motion apparatus comprising: an incrementing wheel mounted for rotation and having arcuately spaced teeth around the periphery thereof, means for constantly urging said incrementing wheel to rotate, and a constantly driven escape wheel having a predetermined number of teeth and mounted to rotate with the teeth thereof in engagement with the teeth of said incrementing wheel to control the movement of said incrementing wheel, said teeth on said escape wheel having a dwell portion and a portion enabling escapement of an incrementing wheel tooth, the teeth of said escape wheel being arcuately spaced from each other a distance less than the width of the teeth on said incrementing wheel and said portion of the escape wheel tooth enabling escapement being laterally deflectable. 6. The intermittent motion apparatus of claim 1 wherein said selectively operable means comprises:

an electromagnet, and an armature controlled by said electromagnet and engageable with said incrementing wheel to hold the same stationary. 7. The intermittent motion apparatus of claim 1 wherein said last mentioned means includes an emitter operable to generate a control signal in synchronism with the engagement of a dwell portion of an escape wheel tooth with an incrementing Wheel tooth.

8. Intermittent motion apparatus comprising: an incrementing wheel mounted for rotation and having teeth spaced around the periphery thereof, an escape wheel having a predetermined number of teeth and mounted to rotate with the teeth thereof in engagement with the teeth of said incrementing wheel, means for constantly driving said escape wheel, and selectively operable brake means for braking said incrementing wheel to hold the same stationary, said teeth on said escape wheel and on said incrementing wheel being so arranged that the teeth on the escape wheel may pass between the teeth on the incrementing wheel when the incrementing wheel is stationary and control the rotation of said incrementing wheel when the incrementing wheel is allowed to rotate. 9. The intermittent motion apparatus of claim 8 wherein said teeth of said escape wheel are resilient so as to flex as they pass between the teeth of said incrementing Wheel when the incrementing wheel is braked.

10. The intermittent motion apparatus of claim 8 including means for constantly urging said incrementing wheel to rotate and wherein said incrementing wheel and said escape wheel are mounted on axes that are at right angles to each other,

6 the teeth of said escape wheel being laterally deflectable so that they may pass between the teeth of said incrementing wheel when the incrementing wheel is braked.

11. The intermittent motion apparatus of claim 8 including means for constantly urging said incrementing wheel to rotate and wherein the teeth on said escape wheel each has a relatively rigid dwell portion allowing substantially no rotation of said incrementing wheel and a relatively flexible end portion allowing rotation of said incrementing wheel when said brake means is disengaged and flexing to allow the teeth of said escape wheel to pass between the teeth of said incrementing wheel when the incrementing wheel is braked.

References Cited UNITED STATES PATENTS 1,273,734 7/1918 Chainat 741.5 2,554,523 5/1951 Clifford 741.5 3,316,769 5/1967 Nordin 74-1.5

MILTON KAUFMAN, Primary Examiner.

US. 01. X.R. 

